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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Biodegradation in water

For assessing the biodegradation of hydroquinone in water under aerobic or anaerobic conditions five valid studies are available. In studies conducted according to OECD Guideline 301C (MITI I), hydroquinone proved to be readily biodegradable, fulfilling the 14 d window criterion (70% biodegradation after 14 d). Under aerobic conditions,1,4-benzoquinone, 2-hydroxy-1,4-benzoquinone, and β-ketoadipic acid were identified as metabolic intermediates, however at low concentrations.

Proposed metabolism pathway under anaerobic conditions: degradation via phenol, cyclohexanol, cyclohexanone to caproic and adipic acid which are further degraded to acetate, propionate, butyrate, CO2, H2and CH4.

Biodegradation in water and sediment: simulation tests

In a laboratory activated sludge unit (equivalent to the set-up of OECD 303 A: Simulation Test – Aerobic Sewage Treatment) using adapted sludge hydroquinone was removed by >=99.9% at influent concentrations up to 275 mg/L. The extent of TOC removal was between 70% and 92% for hydroquinone containing experiments, while it was lower (69%) in the control experiment without hydroquinone and synthetic domestic sewage, only.

Biodegradation in soil

Hydroquinone was degraded in soil within 1 day under laboratory conditions. However, only primary degradation was determined. The detection of a transformation product (which was not identified) indicates that within 1 day mainly primary degradation occurs. Due to the ready biodegradability observed in the screening tests (5.2.1), hydroquinone is expected to be rapidly biodegraded in soils.